Why does hex use letters?

Base 16 needs 16 symbols; after 0-9 we use A (10), B (11), C (12), D (13), E (14), F (15).

Mostly for Unix file permissions (chmod) and some legacy systems. Hex has largely replaced it.

Can I convert negative numbers?

Not in non-decimal bases with this tool. Negative decimals are allowed.

Conversions

Number base converter

Convert a number between the four common bases: binary (2), octal (8), decimal (10) and hexadecimal (16). Fields sync live.

Binary (base 2)

Octal (base 8)

Decimal (base 10)

Hexadecimal (base 16)

How to use this tool

Number bases are everywhere in computing: binary for bits and masks, hex for colors (#FF5733), memory addresses and hashes, octal for Unix permissions (chmod 755). This tool converts instantly between the four main bases: type in any field and the other three update.

Concrete examples

255 decimal → FF hex → 11111111 binary
chmod 755: 111 101 101 binary (rwx r-x r-x)
Web color #A0 = 160 decimal

Frequently asked questions

Why does hex use letters?: Base 16 needs 16 symbols; after 0-9 we use A (10), B (11), C (12), D (13), E (14), F (15).
Is octal still used?: Mostly for Unix file permissions (chmod) and some legacy systems. Hex has largely replaced it.
Can I convert negative numbers?: Not in non-decimal bases with this tool. Negative decimals are allowed.